Changing With The Seasons: Does vitamin D affect mood? Dave G. Downing & David C. R. Kerr, Ph.D. School of Psychological Science, College of Liberal Arts Rationale Seasonality: a change in mood and behavior with the seasons Research shows there is a possible connection between vitamin D levels and mood [1][2] Phototherapy, an evidence-based treatment for those with seasonal affective disorder, was shown not to influence vitamin D levels [3], however… Given that vitamin D is produced when the skin is exposed to sunlight and varies with sun exposure [3], the present study examined the relationships among vitamin D levels, season, and seasonality. Hypothesis Methods Participants recruited at each season and their vitamin D levels were measured from blood samples collected at baseline (T1) and again 5 weeks later (T5). Participants reported their seasonality symptoms across their lifespan using the Seasonal Pattern Assessment Questionnaire (SPAQ) at T5. Vitamin D levels will be relatively: 1) higher, but decreasing in fall; 2) lower, but stable in winter; and 3) higher, but increasing in spring Patterns will be stronger among participants with self- reported seasonality (shown below). Results Repeated measures ANOVA was used to examine mean level and change in vitamin D for individuals in both seasonality groups, and whether any differences depended on season of recruitment Vitamin D levels showed the expected patterns by season. Level [F (2, 178) = 4.49, p <.05] and change [F (2, 178) = 27.7, p <.001] in vitamin D were high, and decreased from T1 to T5 in Fall, remained low and stable in Winter, and were higher and increased in Spring. This pattern did not differ by self-reported seasonality (p = n.s.) Contrary to the hypothesis, individuals with at least moderate seasonality did not show significantly more pronounced seasonal changes in vitamin D in comparison to others (shown below). Discussion Consistent with past research, vitamin D levels decreased in Fall, remained lower in Winter, and increased in Spring for all participants [3]. However, those with self-reported seasonality did not show more pronounced changes in vitamin D. Although not statistically significant, this study found the expected trend where vitamin D levels dropped lower in those who had seasonality than those who do not. Limitations: the design of this study posed challenges in finding the expected interactions. Small sample size, retrospection of the SPAQ, and the between-subjects design were obstacles in gaining a thorough insight into whether or not vitamin D, seasonality, and season are related. Implications: future research could expand on the present study by following a larger sample of participants throughout the entire year, assessing their changes in vitamin D and mood at each season. Participants Measures Vitamin D: Serum concentration of vitamin D (ng/mL) Seasonality: Individuals self-reported changes in mood and vegetative functions with the seasons on the Seasonal Pattern Assessment Questionnaire (SPAQ). Blood Sample Collected T1 Blood Sample Collected Participants Filled Out SPAQ Questionnaire T5 To what degree do the following change with the seasons? (scale 1-4) If you experience changes with the seasons, do you feel that these are problems for you? Sleep length Social activity Mood (overall feel of well being) Weight Appetite Energy level No. 1 Yes 2 If yes, is this problem – mild, moderate, marked, severe, or disabling To what degree do the following change with the seasons? (scale 1-4) If you experience changes with the seasons, do you feel that these are problems for you? Sleep length Social activity Mood (overall feel of well being) Weight Appetite Energy level No. 1 Yes 2 If yes, is this problem – mild, moderate, marked, severe, or disabling Fall (T1) Fall (T5) Winter (T1) Winter (T5) Spring (T1) Spring (T5) Vitamin D Level Trends: non-significant patterns did emerge. As shown here, vitamin D levels dropped lower in Winter (T5) and started lower in Spring (T1) for individuals with seasonality. Recruited: o Fall (n=82) o Winter (n=34) o Spring (n=62) Ages: Ethnicity: White, non- Hispanic (73%) *List of references available upon request* College Women (n=187) Sample SPAQ items: Acknowledgements We thank the John C. Erkkila, M.D. Endowment for Health and Human Performance, Good Samaritan Hospital Foundation for funding; and Adrian Gombart and Balz Frei of the Linus Pauling Institute, and David Zava of ZRT Laboratory for their support. Thanks to Dr. David Kerr for his unrelenting support throughout this project. Contact Information: Dave G. Downing School of Psychological Science Reed Lodge 2950 SW Jefferson Way Corvallis, OR Phone: (541)